$(document).ready(function(){
	$(".img_menu").hover(
		function () {
			whichmenu = "#img" + $(this).attr("id").substr(3,1);
			$(whichmenu).css("cursor", "pointer");			
			$(whichmenu).attr("src", $(whichmenu).attr("src").split(".").join("_s."));
			$(whichmenu).show;
  		},	function () {
		whichmenu = "#img" + $(this).attr("id").substr(3,1);
		$(whichmenu).css("cursor", "default");			
		$(whichmenu).attr("src", $(whichmenu).attr("src").split("_s.").join("."));					
		$(whichmenu).hide;		
 	});
});